The present invention relates to the field of alarm devices which may be mounted on an object to be protected and which are activated in response to one of a plurality of external conditions.
Various alarm devices are known to employ a plurality of activation techniques such that the alarm will be activated with either the object attached to the alarm, or the alarm itself is being tampered with. One such device is disclosed in the U.S. Pat. No. 3,924,254 to Klebold et al who teaches an alarm system having a motion sensitive switch to detect motion of the alarm device and an anti-tamper coil which activates the alarm when the power supply to the alarm device is tampered with. However, the anti-tamper section of the Klebold device requires a constant application of energy to a coil, thereby creating a relatively high power drain in a quiescent state. Furthermore, while the prior art systems such as the Klebold system may provide a separate means for detecting the removal of power from the alarm, they do not provide a separate means for detecting the removal of a ground path for the circuitry in the alarm.